How Volcano Vent Tubeworms Work

Tubeworms thrive on the chemicals and bacteria around vents on the ocean floor.

Ralph White/Terra/Corbis

One of the strangest things about the climate around deep sea vents is that the temperatures are extreme. Extremely different, that is. The water pushing out of the vents can be as hot as 752 degrees Fahrenheit (400 degrees Celsius), but just an inch (3 centimeters) away from the vent opening the water is already down to 36 degrees Fahrenheit (2 degrees Celsius). So most of the organisms living around vents have to put up with temperatures that hover just above freezing. In other words, they're not there for the nice weather. It's all about the chemical stew spewing from the vents [source: Stover].

The main chemical compound coming from the vents is hydrogen sulfide. Bacteria that colonize deep sea vents thrive on the stuff. In turn, tubeworms depend entirely on bacteria for their food — but they have no mouths and no stomachs. What they do have are massive quantities of bacteria lodged inside them — 285 billion bacteria per ounce (28 grams) of tissue, in fact. Actually, beyond its bacterial chums, there's not much to your typical giant tubeworm besides an aorta and some gonads encased in a 4- to 6-foot-long (1.2 to 1.8-meter) white tube rooted in the ocean floor [source: Trivedi].

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Tubeworms are decked out with red plumes on top, but they're not just for looks. The plumes are red because they're full of blood. The hemoglobin in the blood binds to the hydrogen sulfide floating by and moves it down into the tube where bacteria oxidize it and produce the carbon compounds the tubeworms need to live. The tubeworms and their bacteria live in a completely symbiotic relationship, each benefiting from the other [source: Stover].

The only problem is that vents don't vent forever. They can switch on or off suddenly without any notice. And when they switch off, the flow of hydrogen sulfide stops, which means all the organisms in the environs die. And since the vents are isolated from one another like undersea islands, the big question is: How do those tubeworms manage to colonize the next vent that appears far away across the seafloor?